Our experiment is based on static electricity. Rubber and plastic combs and inflated balloons all conduct electricity. When you rub a comb or a balloon through hair it will become negatively charged. Water has no net electrical charges so the comb or balloon will cause some kind of charge towards the water. When the comb or balloon comes near the water, the water that is closest to the balloon or comb will gain a positive charge. The attraction between the comb or ballon (electrons/negatively charged) and the water (positively charged) will end up making a net force for the water, causing the water bend.
So we are going to see whether rubbing a comb or balloon through hair (to attract electrons) really does bend water. We will also be experimenting with whether a plastic comb, a rubber comb, or a balloon causes the water to bend the most.
Procedure
We filled the culvert with cold water and set in the stand. We put the culvert over the sink. We then placed the meter stick across the sink. We opened the culvert to see where on the meter stick the water fell. This was our base line. We combed Ben's hair with the comb 20 times. We held the comb two cm to the left of the culvert. We opened the culvert. We recorded the point on the meter stick where the water fell. We found the distance between this point and the base line. We repeated the experiment six times with each comb and the balloon. When we used the balloon, we rub it on Ben's hair 20 times.
Results
Plastic Comb
Rubber Comb
Balloon
Trial 1
1 cm
1.5 cm
4 cm
Trial 2
.5 cm
1.6 cm
3.2 cm
Trial 3
1 cm
2 cm
5 cm
Trial 4
1 cm
1.8 cm
3 cm
Trial 5
0 cm
3 cm
5 cm
Trial 6
0 cm
2 cm
5 cm
Conclusions
A latex balloon holds a greater electric charge than a rubber comb, which holds a greater charge than a plastic comb. Presumably this is because the latex of the balloon is more attractive to electrons than rubber or plastic. We think something more conductive of electricity would hold less of an electric charge, since it would give up its extra electrons more willingly. However, this may also be related to the different shapes of the combs and the inflated balloons. If we found a latex comb we could test whether the balloons material, shape, or a combination of the two makes the balloon so conductive.
Table of Contents
Relative Conductivity of Rubber and Plastic
Ben, Bekah.
Introduction
Our experiment is based on static electricity. Rubber and plastic combs and inflated balloons all conduct electricity. When you rub a comb or a balloon through hair it will become negatively charged. Water has no net electrical charges so the comb or balloon will cause some kind of charge towards the water. When the comb or balloon comes near the water, the water that is closest to the balloon or comb will gain a positive charge. The attraction between the comb or ballon (electrons/negatively charged) and the water (positively charged) will end up making a net force for the water, causing the water bend.
So we are going to see whether rubbing a comb or balloon through hair (to attract electrons) really does bend water. We will also be experimenting with whether a plastic comb, a rubber comb, or a balloon causes the water to bend the most.
Procedure
We filled the culvert with cold water and set in the stand. We put the culvert over the sink. We then placed the meter stick across the sink. We opened the culvert to see where on the meter stick the water fell. This was our base line. We combed Ben's hair with the comb 20 times. We held the comb two cm to the left of the culvert. We opened the culvert. We recorded the point on the meter stick where the water fell. We found the distance between this point and the base line. We repeated the experiment six times with each comb and the balloon. When we used the balloon, we rub it on Ben's hair 20 times.
Results
Conclusions
A latex balloon holds a greater electric charge than a rubber comb, which holds a greater charge than a plastic comb. Presumably this is because the latex of the balloon is more attractive to electrons than rubber or plastic. We think something more conductive of electricity would hold less of an electric charge, since it would give up its extra electrons more willingly. However, this may also be related to the different shapes of the combs and the inflated balloons. If we found a latex comb we could test whether the balloons material, shape, or a combination of the two makes the balloon so conductive.
References
http://www.newschoolrome.com/html/static_electricity_and_balloon.html
http://www.energyquest.ca.gov/story/chapter03.html
http://phet.colorado.edu/simulations/sims.php?sim=Balloons_and_Static_Electricity
http://www.exploratorium.edu/science_explorer/roller.html